Distribution of plant functional groups in relation to continuous grazing and distance to water sources for livestock in the Arid Chaco, Argentina.

SCAGLIA JUAN; FLORES DANIEL; RAÚL TAPIA; MARIANA MARTINELLI; NAVEA MARIA GABRIELA; DIAZ PELUFFO MARCIA

Rangeland Ecology & Management

ELSEVIER

Año: 2025

In the prairies of the Arid Chaco, the presence of permanent water sources affects the spatial patterns of livestock grazing, generating a gradient of grazing intensity that affects the composition of plant communities and the functioning of the ecosystem. The characteristics of plant species give rise to species-specific responses to environmental stimuli. These characteristics can group species into different functional plant groups that determine the effect of different disturbances on the functioning of the ecosystem. In this context, our study proposes the hypothesis that continuous grazing associated with permanent water sources generates a cumulative livestock pressure that determines different ecological conditions for plant communities in different geomorphological units. Under this hypothesis, we make the following predictions: 1) The spatial distribution of functional plant groups is directly and indirectly influenced by the distribution of water sources. 2) Variation in the quality of forage resources is associated with the distribution of some functional plant groups. Five plant functional groups were defined: annual non-fodder herbaceous plants, perennial non-fodder herbaceous plants, fodder woody plants, fodder herbaceous plants and non-fodder woody plants. The plant functional groups significantly affected were those related to the production of fodder herbaceous plants and non-fodder woody plants. The relationship between the contribution of the functional groups of plants and the forage quality of the plant communities in the geomorphological units studied shows that forage grasses have a positive relationship and non-forage woody plants have a negative relationship. At distances greater than 1250 metres in the alluvial plain and 1900 metres in the piedmont, the growth of forage species increases significantly. This can serve as a reference for planning the distribution of water sources for livestock in semi-arid plains, such as the area studied.